Anatomy & Physiology Nervous System Part I: Neurons

Neurons are the cells of the nervous system and are found in the brain, spinal cord, and other nerves. The nervous system is responsible for sensory reception of signals outside the body, motor stimulation, and processing. Neurons come in many forms and create complex structures containing dendrites, axons, a myelin sheath, and various terminals, nodes, vesicles, and synapses. Signaling occurs via electric charges distributed over action potentials which are transmitted and maintained by sodium, calcium, and potassium ions. Neurons at rest have potentials of -70 mV. This lecture includes the steps of action potentials as well as Saltatory conduction, propagation of the signal, the role of synapses and neurotransmitters, and inhibition vs. excitation. Neurotransmitters include norepinephrine (noradrenaline) and epinephrine (adrenaline), dopamine, serotonin, and endorphins.

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Hi Bryan. 1 question... The movement of Na+ into the axon and K+ out, on your action potential slide. That "pump" is the sodium potassium pump? Also. In regards to the peripheral nervous system, or I guess the nervous system in general what is behind the intensity of a "stimulation"? I'm not sure how to exactly ask my question lol. For example, how does the body distinguish the level of pain you'd feel from the prick of a needle to the pain of it actually puncturing the skin?

1 answer

Last reply by: Bryan CardellaSun Oct 19, 2014 2:20 PM

Post by Ray Gaytanon October 18, 2014

Thank You!!!!!!! Very beneficial and helpful. Breaking down the terms in easy level, I am able to see the big picture.

1 answer

Last reply by: Bryan CardellaTue Aug 19, 2014 5:56 PM

Post by Ikze Choon August 19, 2014

in the example of the presynaptic facilitation: Is it necessary that there is an action potential or are the neurotransmitters from the other neuron enough to stimulate the exocytosis?

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Last reply by: Johanna SerbousekFri Aug 8, 2014 6:42 PM

Post by Gaurav Kumaron July 7, 2014

Do action potentials occur in each node of the neuron?

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Post by Madina Abdullahon April 25, 2014

really helpful,thank you

1 answer

Last reply by: Bryan CardellaMon Mar 10, 2014 6:10 PM

Post by chris sickenbergeron March 10, 2014

your awesome Bryan. its so clear after one of your lessons

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Post by Sandra Egwuonwuon February 16, 2014

*am

1 answer

Last reply by: Bryan CardellaMon Feb 17, 2014 11:04 AM

Post by Sandra Egwuonwuon February 16, 2014

I am basically paid to be an educator student mainly because of you...You teach excellently well.

A: A LOT. In the brain alone, there are approximately 100 billion neurons and each of them has the capability to make thousands or 10s of thousands of connections with neighboring cells, so the number is probably in the 100s of trillions or more (if you include the brain, spinal cord, and peripheral nervous system.) The 100 trillion synapses of the brain go a long way…even though computers currently have the ability to be faster than the human brain, they don’t even come close to matching the storing power or complexity of the human brain.

Nervous System Part I: Neurons

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

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